2546
Chem. Mater. 2002, 14, 2546-2552
Fabrication and Characterization of Polyaniline Monolithic Actuators Based on a Novel Configuration: Integrally Skinned Asymmetric Membrane Hsing-Lin Wang,* Junbo Gao, Jose-Maria Sansin˜ena, and Patrick McCarthy MSJ 586, Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 Received November 16, 2001. Revised Manuscript Received April 9, 2002
We report the synthesis and characterization of polyaniline integrally skinned asymmetric membranes (PANI ISAMs) and their use as chemical and electrochemical actuators. SEM characterization of a PANI ISAM cross section showed a thin dense skin and a microporous substructure with a PANI density gradient. The deformation mechanism of chemical monolithic PANI ISAM actuation was found to result mainly from asymmetric volume expansion/contraction because of the presence/absence of counterions during PANI doping/ dedoping cycles. Actuator performance was affected by acid concentration and film thickness. Our results also show that the deformation mechanism in electrochemical PANI ISAM actuation involves mainly changes in polymer conformation with changes in oxidation state. Because these PANI ISAM actuators are monolithic, that is, they are fabricated without any additional layer (tape, polymer, or gold), their structural stability is expected to be superior to bimorph actuators.
Introduction There has been growing interest in the development of conducting polymer (CP) actuators because they are lightweight, have low operating potential (typically
